Computerized screening for cognitive impairment in patients with COPD

Figures & data

Figure 1 Patient flow with reasons for exclusion and dropout.

Note: CNSVS performance of patients measured in the pre-PR week and week 1 of PR were analyzed as one group (n=220).
Abbreviations: CNSVS, central nervous system vital signs; COPD, chronic obstructive pulmonary disease; PR, pulmonary rehabilitation; wk, week.

Table 1 CNSVS cognitive tests and corresponding cognitive domains

Cognitive domain	Test	Score calculation (min–max)b
Memorya	VeMT – immediate word recognition; delayed word recognition; ViMT – immediate figure recognition; delayed figure recognition	VeMT immediate correct hits + correct passes + delayed correct hits + correct passes + ViMT immediate correct hits + correct passes + delayed correct hits + correct passes (0–120)
Processing speed	SDCT – typing in as many correct numbers from 2 to 9 underneath a series of symbols. Each symbol is linked to a number from 2 to 9, presented in a key table that stays visible during the test	SDCT correct responses − SDCT errors
Psychomotor speeda	FTT – pressing the space bar with the right and left index finger as many times in 10 s SDCT – see: Processing speed	FTT right taps average + FTT left taps average + SDCT correct responses
Reaction timea	Stroop test – part 1: Pressing the space bar as soon as the words RED, YELLOW, BLUE, and GREEN appear; Part 2: Pressing the space bar as soon as the color of the word matches the meaning of the word; Part 3: Pressing the space bar as soon as the word does not match the meaning of the word	(Stroop test Part 2 reaction time correct + Part 3 reaction time correct)/2
Executive functioning	SAT – shifting from one instruction set to another quickly and accurately (matching geometric objects either by shape or by color)	SAT correct responses − SAT errors
Cognitive flexibilitya	SAT – see: Executive functioning; Stroop test – see: Reaction time	SAT correct responses − SAT errors − Stroop test Part 3 commission errors
Complex attentiona	CPT – responding to a target stimulus “B”, while not to any other letter; SAT – see: Executive functioning; Stroop test – see: Reaction time	CPT commission errors + CPT omission errors + SAT errors + Stroop test Part 3 commission errors

Notes:

a The mean of these domain scores is the NCI;

b If applicable.

Abbreviations: CNSVS, central nervous system vital signs; CPT, continuous performance test; FTT, finger tapping test; NCI, neurocognition index; SAT, shifting attention test; SDCT, symbol digit coding test; VeMT, verbal memory test; ViMT, visual memory test.

Table 2 Demographic and clinical characteristics of patients

Characteristic	M/n	SD/%
Age (M, SD)	61.18	8.53; 36–80a
Sex (n, %)
Female	116	52.7
Male	104	47.3
Education years (M, SD)	10.38	2.83
Education level (n, %)
Low	71	32.3
Medium	128	58.2
High	21	9.5
Partner (n, %)
Yes	163	74.1
No	57	25.9
Employed (n, %), n=218
Yes	37	17.0
No	181	83.0
Computer use (n, %)
Never	42	19.1
Sometimes	60	27.3
Frequent	118	53.6
Chronic oxygen (n, %)
Yes	58	26.4
No	162	73.6
Inpatient PR (n, %)
Yes	145	65.9
No	75	34.1
GOLD-stage (n, %)
I – mild	1	0.5
II – moderate	29	13.2
III – severe	91	41.4
IV – very severe	99	45.0
Comorbidity (n, %), n=205
Diabetes	18	8.8
Heart	81	39.5
Lung	25	12.2
Muscular-skeletal	44	21.5
Neurologicb	27	13.2
DART (M, SD), n=211	70.38	14.19
Number of exacerbations (M, SD), n=200	4.49	3.61
Number of hospitalizations (M, SD), n=200	1.66	1.95
FEV1 (L); % predicted (M, SD)	1.05; 38.25	0.48; 15.29
BMI (M, SD)	26.20	5.86
PaO2 (kPa) (M, SD)
Capillary, n=87	8.43	1.16
Arterial, n=132	8.89	1.28
Wmax (W); % predicted (M, SD), n=218	39.36; 29.04	23.49; 15.28
6MWDT (meters) (M, SD)	382.64	102.28
SGRQ total score (M, SD), n=219	65.51	11.55

Notes: Unless stated otherwise n=220;

a minimum–maximum;

b including CVA, lacunar infarct, subarachnoid hematoma, TIA, subdural hematoma.

Abbreviations: 6MWDT, six-minute walking distance test; BMI, body mass index; CVA, cerebrovascular accident; DART, Dutch Adult Reading Test; FEV₁, forced expiratory volume in 1 second; GOLD, Global Initiative for Chronic Obstructive Lung Disease; kPa, kilopascal; PaO₂, partial oxygen pressure in the blood; PR, pulmonary rehabilitation; SGRQ, St George’s Respiratory Questionnaire; TIA, transient ischemic attack.

Table 3 Cognitive domain scores of COPD patients compared to the normative mean with z-tests and percentage impaired per cognitive domain

Cognitive domains	n	M	SD	da	zb	p-valuec	Impairedd
							n	%
Reaction time	214	97.05	14.27	0.20	−2.877	0.002	23	10.75
Psychomotor speed	218	92.66	14.86	0.49	−7.225	<0.001	37	16.97
Executive functioning	217	93.93	17.52	0.40	−5.961	<0.001	43	19.82
Memory (verbal and visual)	214	92.33	14.35	0.51	−7.480	<0.001	44	20.56
Complex attention	212	90.48	19.55	0.61	−9.241	<0.001	46	21.70
Cognitive flexibility	213	92.35	18.05	0.50	−7.443	<0.001	50	23.47
Processing speed	220	88.95	15.70	0.73	−10.927	<0.001	63	28.64
NCI (global cognition)	205	93.33	11.08	0.46	−6.367	<0.001	24	11.71

Notes:

a Cohen’s d effect size, where 0.2≤ d <0.5 is small, 0.5≤ d <0.8 is medium, and d ≥0.8 is large²³;

b One-sample z-test, M =100, SD =15;

c p<0.00625, one-tailed;

d Standard score ≤79 is impaired.

Abbreviation: NCI, neurocognition index.

Figure 2 Percentages of patients per score category per CNSVS domain.

Abbreviations: CNSVS, central nervous system vital signs; NCI, neurocognition index.

Table 4 Comparison of cognitive domain scores between never, sometimes, and frequent computer users with ANOVA

Cognitive domain	Computer use	n	M	SD	df	F	p-valuea	ω^2b
Psychomotor speed	Never	40	85.93	16.31	2, 215	7.883	<0.001	0.059
	Sometimes	60	90.77	14.15
	Frequent	118	95.91	13.85
Reaction time	Never	38	89.66	16.43	2, 211	7.186	0.001	0.055
	Sometimes	60	97.02	13.92
	Frequent	116	99.49	12.92
Complex attention	Never	38	85.84	22.08	2, 209	1.312	0.271	0.003
	Sometimes	59	91.29	19.50
	Frequent	115	91.60	18.63
Cognitive flexibility	Never	39	85.72	20.74	2, 210	3.414	0.035	0.022
	Sometimes	59	92.93	17.65
	Frequent	115	94.30	16.88
Processing speed	Never	42	77.93	14.39	2, 217	21.462	<0.001	0.157
	Sometimes	60	86.17	13.51
	Frequent	118	94.28	14.86
Executive functioning	Never	42	87.88	19.62	2, 214	3.232	0.041	0.020
	Sometimes	59	94.69	16.99
	Frequent	116	95.72	16.64
Memory (verbal and visual)	Never	41	88.22	13.87	2, 211	3.175	0.044	0.020
	Sometimes	58	91.10	12.73
	Frequent	115	94.42	15.00
NCI (global cognition)	Never	35	88.37	11.69	2, 202	5.137	0.007	0.039
	Sometimes	57	92.91	10.89
	Frequent	113	95.07	10.59

Notes: Data in df are presented as: df between groups, df within groups.

a p<0.05;

b Omega squared effect size where 0.010≤ ω² <0.059 is small, 0.059≤ ω² <0.138 is medium, and ω² ≥0.138 is large.²⁵

Abbreviations: ANOVA, analysis of variance; NCI, neurocognition index.

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